1. Field of the Invention
The present invention relates generally to electronic marker systems and more specifically it relates to a locator plug system for efficiently locating utility services that utilize a plug.
2. Description of the Related Art
Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field.
Cleanout fittings for wastewater utility service lines and the like have been in use for years. A two-way cleanout fitting generally has a T-shaped structure with the lower horizontal portion fluidly connected within the wastewater pipe and with an upper tube extending upwardly from the horizontal portion as illustrated in FIG. 1 of the drawings. In addition, a threaded plug is threadably insertable within a threaded upper end of the upper tube. The threaded plug is removed to provide access to the wastewater pipe with a plumbing snake or the like. The cleanout fitting may be comprised of a two-way cleanout fitting which provides for directing the plumbing snake or like in both directions within the wastewater pipe.
Electronic marker systems (passive or active) for marking utility services have been in use for years. A “passive” marker is basically a wire coil and capacitor surrounded in a protective envelope, which is then buried adjacent to the cable, pipe, or other object to be located. The marker is self-contained, with no external, accessible connections. Minnesota Mining & Manufacturing Co. (“3M”) markets several kinds of passive markers for different applications as part of its Scotchmark Electronic Marker System (“ScotchMark” is a registered trademark of 3M). See also U.S. Pat. No. 4,761,656 issued to Cosman et al. on Aug. 2, 1988. Passive markers are activated by radiating a signal into the ground in the area where the marker is expected to be found. The signal is emitted via an inductive coil held close to the surface. When the coil is directly over, or near, the passive marker (which is itself an inductive coil), the marker accepts energy within its band pass and stores it, reaching a sustained amplitude during the transmission cycle. When the transmission cycle ends, the marker re-emits the signal with an exponentially decaying amplitude. A second coil within the transceiver unit acts as a receiving antenna which detects the re-radiated signal, alerting the locating technician with an audible tone or other indicator means. However, none of the electronic marker systems available today provide for a plug that incorporates the electronic marker technology.
Hence, to effectively mark a cleanout fitting within a wastewater pipe, the installer not only has to insert a plug into the cleanout fitting, they have to also position an electronic marker within the meter box. Unfortunately, this is not only time consuming but the installer may forget to position an electronic marker within the meter box prior to the meter box being covered with dirt thereby making it difficult to later locate the cleanout fitting.
While these devices may be suitable for the particular purpose to which they address, they are not as suitable for efficiently locating utility services that utilize a plug. Conventional electronic marker systems do not provide for a plug that integrates electronic marker technology into a single and easy to utilize unit.
In these respects, the locator plug system according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing provides an apparatus primarily developed for the purpose of efficiently locating utility services that utilize a plug.